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‼️Biology‼️ > Topic 1 - Key concepts in Biology > Flashcards

Topic 1 - Key concepts in Biology Flashcards

1
Q

What is a eukaryotic cell?

A

A cell that contains a nucleus. Eukaryotic cells are complex and include all animal and plant cells.

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2
Q

What is a prokaryotic cell?

A

A cell that doesn’t contain a nucleus. Prokaryotic cells are smaller and simpler and include bacteria.

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3
Q

What is a eukaryote?

A

An organism made up of eukaryotic cells.

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4
Q

What is a prokaryote?

A

A single-celled organism, a prokaryotic cell.

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5
Q

What can organisms be classed as?

A

Eukaryotes or Prokaryotes.

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6
Q

What are different parts of a cell known as?

A

The sub cellular structures.

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7
Q

What sub cellular structures does an animal cell have?

A
  • Nucleus
  • Cytoplasm
  • Cell Membrane
  • Ribosomes
  • Mitochondria
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8
Q

What sub cellular structures does a plant cell have?

A
  • Nucleus
  • Vacuole
  • Cytoplasm
  • Cell membrane
  • Chloroplasts
  • Mitochondria
  • Ribosomes
  • Cell Wall
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9
Q

What are organelles?

A

All the bits that make up a cell

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10
Q

What is a nucleus?

A

A nucleus contains genetic material that controls activities in the cell. This genetic material is arranged into chromosomes. Found in Plant and Animal cells.

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11
Q

What is a cytoplasm?

A

Gel-like substance where most of the chemical reactions happen. It contains enzymes that control these chemical reactions. Found in Plant and Animal cells.

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12
Q

What is a cell membrane?

A

Holds the cell together and controls what goes in and out. Found in Plant and Animal and Bacteria cells.

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13
Q

What are ribosome?

A

These are involved in translation of genetic material in the synthesis of proteins. Found in Plant and Animal and Bacteria cells.

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14
Q

What is a mitochondria?

A

These are where most of the reactions for respiration take place. Respiration transfers energy that the cell needs to work. Found in Plant and Animal cells.

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15
Q

What is a vacuole?

A

Contains cell sap; a weak solution of sugar and salts. It maintains the internal pressure to support the cell. Found in Plant cells.

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16
Q

What are chloroplasts?

A

These are where photosynthesis occurs, which makes food for the plant. They contain a green substance called chlorophyll. Found in plants.

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17
Q

Whats a cell wall?

A

A rigid cell wall is made of cellulose. It supports the cell and strengthens it. Found in Plant and Bacteria cells.

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18
Q

What sub cellular structures does Bacteria have?

A
  • Plasmid
  • Cell Membrane
  • Ribosomes
  • Cell Wall
  • Flagellum
  • Capsule
  • Chromosomal DNA
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19
Q

What is the chromosomal DNA?

A

Controls the cell’s activities and replication. It floats free in the cytoplasm. Found in Bacteria cells.

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20
Q

What is a plasmid?

A

Small loops of extra DNA that aren’t part of the chromosome. Plasmids contain genes for things like drug resistance and can be passed between bacteria. Found in Bacteria cells.

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21
Q

What is a flagellum?

A

A long, hair-like structure that rotates to make the bacterium move. It can be used to move the bacteria away from harmful substances like toxins and towards beneficial things like nutrients or oxygen. Found in Bacteria cells.

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22
Q

What makes a specialised cell?

A

Cells that have a structure which makes them adapted to their function are called specialised cells. They include Egg, Sperm and Ciliated Epithelial Cells.

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23
Q

What happens in sexual reproduction with the egg and sperm cells?

A

Egg and sperm cells are specialised for reproduction. The nucleus of an egg cell fuses with the nucleus of a sperm to create a fertilised egg, which then develops into an embryo. The nucleus of an egg and sperm cell contain half the number of chromosomes that Is in a normal body cell(haploid). This means that when they combine at fertilisation the resulting cell will have the right amount of chromosomes.

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24
Q

Whats a diploid cell?

A

A cell that contains 2 sets of chromosomes = 46 chromosomes.

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25
Q

Whats a haploid cell?

A

A cell that contains 1 set of chromosomes = 23 chromosomes.

26
Q

How is an egg cell adapted to its function?

A

The main function of an egg is to carry the female DNA and to nourish the developing embryo in the early stages.

1) It contains nutrients in the cytoplasm to feed the embryo.
2) It has a haploid nucleus
3) Straight after fertilisation, its membrane changes structure to stop any more sperm getting in (gel coat). This makes sure the offspring end up with the right amount of DNA.

27
Q

How is a sperm cell adapted to its function?

A

The function of a sperm is to transport the male’s DNA to the female’s egg.

1) A sperm cell has a long tail so it can swim, to the egg.
2) It has lots of mitochondria in thimble section to provide the energy (from respiration) needed to swim this distance.
3) It has an acrosome at the front of the head, where it stores enzymes needed to digest its way through the membrane of the egg cell.
4) It contains a haploid nucleus.

28
Q

How are ciliated epithelial cells specialised?

A

Ciliated epithelial cells are specialised for moving materials. Epithelial cells line the surfaces of organs. Some of these have cilia on the top surface of the cell. The function of these cells is to move substances. The cilia beat to moved substances in one direction, along the surface of the tissue. Moves mucus and dirt.

29
Q

What are microscopes?

A

Microscopes use lenses to magnify images and increase the resolution of an image.

30
Q

Whats resolution?

A

Resolution means how well a microscope distinguishes between two points that are close together. A higher resolution means that the image can be seen more clearly and in more detail.

31
Q

What are light microscopes?

A

They were invented in the 1590s. They work by passing light through the specimen. They let us see things like nuclei and chloroplasts, can use them to study living things.

32
Q

What are electron microscopes?

A

They were invented in the 1930s. They use electrons rather than light. They have a higher resolution and magnification than light microscopes, so they let us see much smaller things - like the internal structure of mitochondria and chloroplasts. This has allows a much greater understanding of how cells work and the role of sub cellular structures.

33
Q

What is the total magnification calculation?

A

Total magnification = eyepiece lens magnification x objective lens magnification

34
Q

What is the other magnification formula (if you don’t no the lenses used)?

A 
Magnification = image size ➗ real size
M = I➗A
35
Q

Why should you estimate?

A

Estimating can help you check that your answer is correct. To estimate an answer, round both numbers to 1 significant figure and do the calculation.

36
Q

Whats the relationship between quantitate units in relation to cells & standard form?

A

Millimetre (mm) X 10-3m
❌1000 ➗1000
Micrometre (μm) X 10-6m
❌1000 ➗ 1000
Nanometre (nm) X 10-9m
❌1000 ➗ 1000
Picometre (pm) X10-12m

37
Q

What are enzymes?

A

Living things produce enzymes which act as biological catalysts. Enzymes reduce the need for high temperature and we only have enzymes to speed up the useful chemical reactions in the body.

38
Q

What is a catalyst?

A

A catalyst is a substance which increases the speed of reaction, without being changed or used up in the reaction.

39
Q

Why do enzymes having special shapes, Whats the lock and key method?

A

So that they can catalyse reactions. Every enzyme has an active site, Enzymes only work with one substrate. They are said to have a high specificity for their substrate. This is because, for the enzyme to work, the substrate has to fit into the active site. If the substrate’s shape doesn’t match the active site’s shape, then the reaction won’t be catalysed. - This is the lock and key method.

40
Q

Whats a substrate?

A

The molecule changed in the reaction.

41
Q

Whats the active site?

A

Part which has a shape complimentary to the substrate, where it joins to catalyse the reaction.

42
Q

What happens the the active site changes shape?

A

Changing the shape of the active site of an enzyme will cause its reaction to slow down until the shape has changed so much that the substrate no longer fits. When this happens the reaction stops. At this point we say the enzyme is denatured and permanently damaged.

43
Q

Whats the effect of temperature on enzyme activity?

A

Changing the temperature changes the rate of an enzyme-catalysed reaction. A higher temperature increases the rate at first, but if it gets too hot, some of the bonds holding the enzyme together break. This changes the shape of the enzyme’s active site, so the substrate won’t fit anymore. The enzyme is said to be denatured. All enzymes have an optimum temperature they work best at.

44
Q

Whats the effect of pH on enzyme activity?

A

The pH affects enzymes, if its too high or too low the pH interferes with the bonds holding the enzyme together. This changes the shape of the active site and denatures the enzyme. All enzymes have a optimum pH that they work best at. It’s often neutral pH 7.

45
Q

Whats the effect of substrate concentration on enzyme activity?

A

Substrate concentration affects the rate of reaction -the higher the substrate concentration, the faster the reaction. This is because it’s more likely that the enzyme will meet up and react with a substrate molecule.

46
Q

What is rate a measure of?

A

How much something changes over time.

47
Q

What is the rate of reaction calculation?

A

rate = change ➗ time

48
Q

What do enzymes do in breakdown?

A

Enzymes break down big molecule (proteins,lipids and some carbohydrates) into smaller components so that they can be used for growth and other life processes.

49
Q

What happens with Enzymes and carbohydrates?

A

Enzymes called carbohydrases convert carbohydrates into simple sugars.
Example- Amylase is an example of a carbohydrase. It breaks down starch.

50
Q

What happens with enzymes and proteins?

A

Proteases convert proteins into amino acids.

51
Q

What happens with enzymes and Lipids?

A

Lipases convert lipids into glycerol and fatty acids.

52
Q

What happens when carbohydrates, proteins and lipids synthesise?

A

Carbohydrates can be synthesised by joining together simple sugars.
Proteins are made by joining amino acids together. Enzymes catalyse the reactions needed to do this.
Lots of enzymes are involved in the synthesis of lipids from fatty acids and glycerol.

53
Q

What is synthesis?

A

The combining of separate elements or substances to form a coherent whole.

54
Q

What is diffusion?

A

The overall movement of particles from an area of higher concentration to an area of lower concentration. Diffusion happens in both liquids and gases- because the particles in these substances are free to move about randomly.
Only very small molecules can diffuse through cell membranes - glucose, amino acids, water and oxygen.

55
Q

What are key features of diffusion?

A
  • Particles move with brownian motion = vibrate
  • Higher temperature = more movement
  • It follows the concentration gradient, high to low
  • Passive process - doesn’t take any extra energy in
  • It is the spreading of particles
56
Q

What is osmosis?

A

The overall movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration.

57
Q

What are key features of osmosis?

A
  • The diffusion of water
  • Passive process - doesn’t take in extra energy
  • Moves down the concentration gradient, high - low
58
Q

What is active transport?

A

The movement of particles across a membrane against a concentration gradient, using energy transferred during respiration.

59
Q

What are key features of active transport?

A
  • Active process - Takes energy in - energy comes from the ATP which is found in the mitochondria
  • Goes against the concentration gradient, high - low
    example: plants absorbing minerals
60
Q

How do you calculate the percentage change in osmosis?

A

percentage change = (final mass - initial mass) ➗ initial mass ❌100

‼️Biology‼️ (5 decks)

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